Electrical connection between electrical contact pads on independent structures, such as between two printed circuit boards (PCBs), is presently achieved through several methods. Most methods require soldering. Any hand soldering must be done with great care with microelectronics, as minute electrical traces can be damaged easily and microelectronic parts may be dislodged or may be damaged by the heat of a soldering iron.
An example of such a connection is a connection between an electroluminescent (EL) backlight panel and a PCB, in a mobile handheld device, for example. An EL backlight panel is connected to a PCB that has circuitry to drive the EL panel. For connecting an EL backlight panel on a liquid crystal display (LCD) module to a PCB, hand soldering the pads of the EL panel directly to the PCB is undesirable since the phosphor layer used in an EL is extremely sensitive to humidity and temperature changes and the EL panel is thus easily damaged by heat and moisture. The laminate used to hold an EL panel together is also sensitive to humidity and heat. Often delamination occurs when an EL panel is exposed to extreme changes in heat and humidity. In small electronic devices, hand soldering is also difficult to achieve because of the limited amount of space that is usually allowed between the LCD module and the PCB.
Another method of connecting the contact pads of an EL backlight panel to a PCB is to solder a wire from a contact pad of the panel to the corresponding contact pad of the PCB. This type of connection is untidy and occupies valuable room in small electronic devices.
Flex connection is also used as a connection means between an EL backlight panel and a PCB. “Flex” is difficult to work with in assembly since it can be damaged easily when handled. A fold or tear in the flex breaks the electrical connection between the EL panel and the circuitry on the PCB rendering the EL panel inoperative.
Through-slot in a PCB is another connection method between an EL backlight panel and a PCB. The through-slot method requires a hole drilled through the PCB. The hole is plated. The connection for the EL panel in this case is in the form of tabs or pins extending out from the panel rather than pads on the panel. The tabs are placed in the slot and screwed or clamped into the slot. Using an EL backlight panel that has tabs to connect to the EL drive circuitry requires more real estate within an electronic device. As electronic devices miniaturize, space savings within the device become essential.
Both flex connection and through-slot methods require soldering and do not allow for movement between the two boards. When enclosed within an electronic device, accommodating some movement between the PCBs is necessary especially when considering shear forces on the device in the event that it is dropped.
There is, therefore, a need for an improved means of making connections between EL panel contact pads and PCB contact pads that does not require soldering. There is also a need for a connector that requires minimal space to fit between an EL panel on an LCD module and the PCB that are used in a small electronic device.